Potential biological attacks against large scale civilian populations have become an important issue in homeland security. By way of example, the anthrax cases in the United States in 2001 and the ricin case on Capitol Hill in 2004 have proven that the threat of a biological attack is real. In order to thwart any potential biological attack, the development of a civilian biodefense plan is crucial. Consequently, there has been an enormous effort to develop practical and efficient biosensors in recent years.
Most present biosensors take advantage of biologically active materials for high sensitivity and selectivity. In general, the biosensor includes a biorecognition structure (e.g., a membrane) in contact with or interrogated by a transducer. The biologically active material recognizes a particular biological molecule through a reaction, specific adsorption, or other physical or chemical process, and the transducer converts the output of this recognition into a usable signal, usually electrical or optical. Many approaches have been explored to achieve ultra-sensitive detection of bio-species. These biodetection approaches can be categorized as either an engineering-oriented approach or a biological-oriented approach. In other words, most biodetection schemes are either based on relatively complex electronic, photonic and/or electrochemical methods or more elegant biomolecular methods (e.g. enzyme linked immunosorbent assay, or ELISA) typically with an optical or spectrometry-based readout.
By way of example, one process utilizes photonics integrated on a microchip to study the interaction between the optical field and the target bio-analyte. Because most biorecognition processes occur in an aqueous ambient, this approach requires the integration of photonics, highly sensitive microelectronics and microfluidic systems on a single microchip. The use of ion-channel switches as biosensors has also been explored, but the bioelectronic interface is a delicate one. Often, when an approach promises very high sensitivity, the output signal from the biorecognition is very small, thus requiring extremely highly-sensitive on-chip microelectronics for signal amplification, processing and wireless transmission. The high demand of these approaches on system integration and high sensitivity photonics and electronics circuitry presents a big challenge to the biosensors in terms of cost, reliability and power consumption. The more biomolecular based approaches, like ELISA, are simple, but typically require a macro scale spectrometry system to quantify the output.
Therefore, it is a primary object and feature of the present invention to provide a bioagent detection device that is highly sensitive and selective.
It is a further object and feature of the present invention to provide a bioagent detection device that is small in size and weight and is inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a bioagent detection device that provides continuous monitoring of a user selected environment.
In accordance with the present invention, a detection device is provided for detecting the presence of an agent in a fluid. The device includes a membrane having first and second sides. The membrane allows passage of a stimulus therethrough in response to presence of the agent. A source is positioned on a first side of the membrane. The source sources the stimulus toward the membrane. A detection structure is disposed on the second side of the membrane for detecting the stimulus.
The detection device includes a body that defines a first chamber for accommodating the membrane therein. The membrane is fabricated from a polymeric material that dissolves in response to exposure to the agent. The source includes an ultraviolet light emitting diode for generating ultraviolet light having an intensity. The ultraviolet light is the stimulus. The detection structure includes an ultraviolet light detector. The ultraviolet light detector generates an output voltage in response to the intensity of the ultraviolet light detected. A mask is positioned between the source and the detection structure. The mask prevents passage of the stimuli therethrough.
In accordance with a further aspect of the present invention, a detection device is provided for detecting the presence of an agent in a fluid. The detection device includes a body defining a chamber. The chamber accommodates the flow of fluid therein. A membrane is disposed in the chamber of the body. The membrane allows for the passage of a stimulus therethrough in response to presence of the agent in the chamber. A source is positioned on a first side of the body. The source directs the stimulus toward the membrane. A detection structure is disposed on the second side of the body for detecting the stimulus.
The stimulus is ultraviolet light and the source includes an ultraviolet light emitting diode for generating the ultraviolet light. The detection structure includes an ultraviolet light detector. The ultraviolet light detector generates an output voltage in response to the intensity of the ultraviolet light detected. The membrane is fabricated from a polymeric material that dissolves in response to exposure to the agent. A mask is positioned between the source and the detection structure. The mask prevents passage of the stimulus therethrough. The body includes an upper surface and lower surface. The chamber extends through the body and the mask is coated on the lower surface of the body. It is contemplated for the ultraviolet light to be at a predetermined wavelength and for the membrane to have a different absorption of light than the fluid at the predetermined wavelength.
In accordance with a further aspect of the present invention, a method of detecting the presence of an agent in a fluid is provided. The method includes the steps of engaging a membrane with the fluid and generating a signal in response to detection of a stimulus directed at the membrane.
The membrane is formed from a polymeric material that dissolves in response to exposure to the agent. The step of generating a signal includes the additional steps of directing the stimulus having an intensity at the membrane and detecting the stimulus. An output voltage is generated in response to the intensity of the stimulus detected. The stimulus is directed toward a first side of the membrane and the stimulus is detected on a second side of the membrane.
The method may also include the additional steps of positioning the membrane in a chamber of a microfluidic device and flowing the fluid through the chamber. The stimulus is ultraviolet light at a predetermined wavelength. The membrane has a different absorption of light than the fluid at the predetermined wavelength.